Security systems alert occupants of a dwelling and emergency authorities of a violation of premises secured by the security system. A typical security system includes a controller connected by wireless or wired connections to sensors deployed at various locations throughout the secured dwelling. In a home, sensors are usually deployed in doorways, windows, and other points of entry. For example, motion sensors can be placed strategically within the home to detect unauthorized movement, while smoke and heat sensors can detect the presence of fire.
Security systems are usually connected to a central monitoring service system via a telecommunications line coupled to a public switched telephone network (PSTN). The central monitoring service system can be maintained by a security service provider and continuously monitors all activated subscriber security systems for alarms. Sensor activity occurs when a sensor detects, for example, an opening of a door or window, or presence of movement, or a fire. Sensor activity causes the sensor to send a signal to the controller of the security system. Responsive to receiving the signal, the controller can determine whether the signal represents an alarm condition and, if so, issue an audible alarm to alert the occupants of the dwelling and can originate a data transmission to the central monitoring service system via the telecommunications line. Upon receiving notification of an alarm, the central monitoring service system can determine the type of activity, attempt to contact the dwelling occupants, and alert appropriate authorities of an emergency situation.
Typically, the telecommunications line interconnecting the security system to the central monitoring service system is the dwelling occupant's telephone line. This line usually emanates and is accessible from the exterior of the dwelling. It is this telecommunications line which delivers a security breach signal to the central monitoring service system via a PSTN.
FIG. 1 is a simplified block diagram illustrating a typical connection between a PSTN and a security system. Building 100 is coupled to PSTN 110 via a network interface device (NID) 120. Typically, NID 120 demarcs the hardware associated with PSTN 110 and the hardware (e.g., building wiring) associated with building 110. When building 100 has a security system, or is configured to accommodate a security system, NID 120 is coupled via building wiring (e.g., twisted pair) to an RJ31X jack 130. The RJ31X jack is typically inserted between an NID and the first telephone jack within a building. An alarm controller unit 140 for a security system can be coupled to the building wiring via RJ31X jack 130. As will be discussed more fully below, this permits a security system to disconnect phones in the building (e.g., coupled to telephone jacks 150-180) in order to transmit an alarm signal to a central monitoring service system via PSTN 110. An RJ31X jack also allows a building's phone system to behave normally if a security system is not connected to the RJ31X jack.
FIG. 2 is a simplified block diagram illustrating an example of a typical voice over Internet protocol (VOIP) connection to a building's telephone wiring. Building 100 is still configured to be coupled to PSTN 110 via NID 120 which is then coupled to RJ31X jack 130. RJ31X jack 130 has connections to both an alarm controller unit 140 and a set of connected phone jacks 150-180 (e.g., in a daisy-chain configuration). FIG. 2 illustrates that a telephone jack 180 is further coupled to an analog telephone adapter (ATA) 210. ATA 210 converts telephone analog signals to digital signals that can be transmitted on a broadband network (e.g., Internet 230). ATA 210 is coupled to a broadband modem 220 (e.g., a cable modem or DSL modem) which is further coupled to a wide area network such as Internet 230. In order for a proper installation of VOIP telecommunications, building 110 should be disconnected from PSTN 110 in order to avoid, for example, improper voltages associated with VOIP from being transmitted onto PSTN 110. Disconnecting is typically performed at NID 120 by manually disconnecting a linkage between PSTN 110 and the building wiring at a demarc point within NID 120. One drawback of a typical VOIP connection is that severing the connection between building 100 and PSTN 110 typically requires a service visit by a representative of the provider of PSTN 110 to perform the disconnection.
Another drawback of a VOIP connection such as that illustrated in FIG. 2 is alarm controller unit 140 cannot perform the task of disconnecting the home phones prior to sending out an alarm signal. This is because the security system is no longer between the building telephone wiring and the external telecommunications network. A further disadvantage of using a legacy security system in a VOIP environment is that such security systems are typically unreliable in a VOIP environment. VOIP data compression as well as multiple analog-to-digital and digital-to-analog conversions typically involved in VOIP transmission can distort alarm signals sent by a security system, thereby making them unusable by the central monitoring service system.
It is therefore desirable to provide a solution in which a legacy security system can function in a VOIP environment without loss of data. It is further desirable to provide a mechanism by which a switch over from PSTN-based telecommunications to an alternative technology-based telecommunication (e.g., broadband or cellular) can be provided without having a person manually disconnect a building from a PSTN by severing a connection within an NID.